Assuming the transformer in Fig. I.19 ideal,the effective value of the load seen by thesource isa.

0.5



b.

50



c.

500



d.

5000



20.

If an electrical transformer and a mechanicalgear system are considered analogous to eachother, the equivalent quantity of thetransformer primary voltage in the gear systemwill bea.

angular speedb.

displacementc.

torqued.

moment of inertia21.

If a unit ramp input v(t) is applied to thecircuit shown in Fig. I.21, then the steady statevalue of the output will bea.

0.002b.

5c.

500d.

200022.

An analog dc ammeter of full scale current of 1 mA is obtained by connecting a shuntresistor of 11



in parallel with agalvanometer having a full scale current of 100



A. The value of shunt resistor requiredfor obtaining an ammeter of full scale currentof 10 mA using the same galvanometer isa.

0.9



b.

1.0



c.

1.1



d.

10.0



23.

An average responding analog ac voltmeterusing half wave rectifier to read RMS value of the input sinusoidal voltage. If the meter reads24 V for a square wave input with zero mean,the actual RMS value of the input isa.

242

V



b.

242

V

c.

482

V



d.

242

V



24.

A resistance is measured by the voltmeter-ammeter method. The voltmeter reading is 25V on the 100 V scale and the ammeter readingis 250 mA on the 500 mA scale. Both metersare accurate within ±1 per cent of full-scalereading. The maximum possible error, inpercent of measured value of the resistor is

QUESTION NUMBER 21-50CARRY 2 MARKS EACH

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a.

± 2%b.

± 2.5%c.

±4%d.

±6%25.

An energy meter makes 200 revolutions of disc per unit of energy. The meter is tested byconnecting to a load of 20 A at pf 0.8 laggingin 250 V mains for one hour. If the observednumber of revolutions is 760, the percentageerror in the meter isa.

0.5% fastb.

2.5% fastc.

5% slowd.

25% slow26.

The ac bridge given in Fig. I.26 is balanced at



= 1000 rad/s. The value of the unknowninductor L isa.

1 Hb.

0.1 Hc.

0.5 mHd.

0.2 mH27.

An RTD having a sensitivity of 0.4



/°C isconnected in a dc bridge having 100



fixedresistors in other three arms. The bridgesupply is 5.4 V with the RTD connected tozero potential and the bridge is balanced at0°C. At room temperature the bridgeunbalanced output voltage is 0.2 V with theRTD side of the output being positive. Theroom temperature isa.

6.4°Cb.

15°Cc.

25°Cd.

40°C28.

The volumetric flow rate (Q) for a turbineflowmeter with 8 blades in the rotor is givenby Q = k



, where the constant k = 2 × 10

–5

m

3

/rad and



is the rotor angular velocity inrad/s. If a proximity device used to pick-uppresence of rotor blades gives output of 48pulses/s, the flow rate isa.

3



× 10

–5

m

3

/sb.

24



× 10

–5

m

3

/sc.

9.6



× 10

–4

m

3

/sd.

12



× 10

–4

m

3

/s29.

Which of the following conditions ensures thatexactly two roots of s

3

+ as

2

+ s + c = 0 lie inthe right half of the s-plane?a.

a > 0, c > 0 and a > cb.

a >0, c > 0 and a < cc.

a > 0 and c < 0d.

a < 0 and c = a30.

The loop transfer function of a unity feedback system is given by

     

114

s s K G ss s

  

. For0



K





, its root locus starts froma.

s = –1 and s = –4b.

s = –1 + j and s = –1 – jc.

s = 1 and s = –



d.

s = –3+

6

and s = –3–

6

31.

The approximate transfer function of a systemwith the following frequency response is



(radian/s)

0.1 0.3 3 30

Gain in dB

-20 -20.5 -26 -60

Phase inDegree

0 0 -90 -180a.

 

2

0.93

s



b.

 

0.93

s s



c.

  

0.913

s s

 

d.

  

0.9130

s s

 

32.

The diagonal form of the state spacerepresentation of a SISO system with thetransfer function